Clinical studies have shown some positive effects from wearing a tDCS (Transcranial Direct Current Stimulation) unit on one’s head. The studies are careful to elaborate the exact placement of the electrodes normally using the 10-20 system. There are already proposals for for higher resolution probe placement such as 10-10 and 10-5 which would reduce probe spacing in areas from 20% down to 5%.
Each site has a letter to identify the lobe and a number to identify the hemisphere location. The letters F, T, C, P and O stand for frontal, temporal, central, parietal, and occipital lobes, respectively. (Note that there exists no central lobe; the “C” letter is used only for identification purposes.) Even numbers (2,4,6,8) refer to electrode positions on the right hemisphere, whereas odd numbers (1,3,5,7) refer to those on the left hemisphere. A “z” (zero) refers to an electrode placed on the midline.